Short-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	$ 19,606	$ 18,114
Short-term Investments, Unrealized Gains		3
Short-term Investments, Unrealized Losses	(44)	(5)
Short-term investments	19,562	18,112
Corporate bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	15,977	15,166
Short-term Investments, Unrealized Losses	(34)	(5)
Short-term investments	15,943	15,161
Government bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term Investments, Amortized Cost	3,629	2,948
Short-term Investments, Unrealized Gains		3
Short-term Investments, Unrealized Losses	(10)
Short-term investments	$ 3,619	$ 2,951